Will those that are saying it won't be simple please explain themselves beyond 'There's a lot of code'? Also, are you programmers or do you just know a bit of programming?
I'm a programmer - nearly 35 years of learning and over 20 years commercial experience. It's mostly business application experience, but I did do a lot of games programming when I was younger (but that's not really relevant because of the changes in programming methods since then).
No-one can say whether this would be a *relatively* easy addition, or a massively difficult one unless they are part of the development team that works on the application. No-one here knows how it was built, but they will make assumptions based on small amounts of knowledge of other products.
There are literally millions, if not billions, of ways that this game could have been built. We know nothing other than what we've seen in some data and model files, and they do not even vaguely hint at how the application uses them.
To say it's either easy or difficult is a statement born of ignorance. We simply do not know.
I see your point, but since the programming team for this game have already added a new mode (capture) and will have had to create the game modes in the first place, it stands to reason that adding a new mode shouldn't present many challenges to them - Well, nothing they've come across before anyway
So no, it's not born of ignorance to say it should be simple for them to add the mode. Again, simple is relative - In this case I'd class simple as "Won't cause too many technical difficulties to implement".
It is ignorance. You say they added capture mode but know nothing of how that was done. It may have been in the game on release day. Ignorance means you do not know so don't take it personally when I say it's an ignorant response.